Only three of the key questions were directly asked by the committee. Some of the questions were broadly alluded to, but the MPs favoured general soft questions rather than forensic probing.

The MPs' performance on the key questions is detailed below, with the response from Sir Iain Lobban, director of GCHQ; Sir John Sawers head of MI6, and Andrew Parker head of MI5.

1 Should Britain's intelligence agencies become more transparent to encourage greater public confidence, and if so how?

Former Labour minister Hazel Blears asked: "Is there the possibility to have a more informed dialogue with the public?"

Lobban replied: "The pat answer is that there are very good safeguards in place … If your activities pose a genuine threat to the national or economic security of the United Kingdom there is a possibility that your communications will be monitored, as in we will seek to read, we will seek to listen to you. If you are not, and you are not in contact with one of those people, then you won't be, and we are not entitled to."

Parker added: "The issue about balancing powers and transparency … are matters principally for ministers to lead on and for parliament to set law about, that we then abide by."

2 Why weren't the cabinet and the National Security Council allowed to know about GCHQ's mass surveillance programmes?

Not asked

3 Why have the agencies resisted calls for an overhaul and updating of surveillance laws?

Sir Menzies Campbell asked: "Is the existing legal framework adequate to deal with the enormous consequences of the revolution in technology?"

Lobban replied: "The laws were drafted to be technology neutral. I think the draftsmen did a pretty good job. [The law] insists upon necessity and proportionality. They are as relevant now as when the laws were drafted. They guide the way that we work … But if Parliament chooses to have a debate, that's fine by me … I want to stress the role of [intelligence] commissioners. As technology moves on, we talk to them about our methods."

4 What action, if any, has been taken to reduce the number of people (estimated to be 850,000 employees and contractors) who have access to the secret material uncovered by the Guardian?

Committee chairman Sir Malcolm Rifkind asked: "Can we assume that you are having discussions with the your American colleagues about the hundreds of thousands of people who appear to have access to your information?"

Parker said: "All three of us are involved in those discussions."

He added: "We have very tightly controlled IT access, and arrangements for who can download what."

5 How many people are working on GCHQ's Tempora program which analyses calls, emails and Google search traffic coming in and out of the UK?

The Tempora program was not mentioned once by name during the session, and the Tory MP Mark Field suggested the committee was not aware of it until Edward Snowden's disclosure. He said: "We were very much aware of your capabilities in the past, but we weren't aware of the intricacies."

Field went on to ask: "While we appreciate that a lot of this is confidential about the sort of co-operation you have with other overseas agencies, will you give us an assurance that at the earliest opportunity in a closed session of this committee you will give us a comprehensive update on collaborations that were taking place with overseas intelligence agencies?"

Lobban replied: "I would be very happy to do so."

Rifkind asked: "Why do you think it is necessary to collect information on the majority of the public in order to protect us from the minority of potential evil-doers."

Lobban replied: "We do not spend our time listening to the telephone calls or reading the emails of the vast majority. That would not be proportionate. It would not be legal, we do not do it. We can only look at the content of communications, where there are very specific legal thresholds that have been met.

"We don't want to delve into innocent emails and phone calls. I don't employ the kind of people who would. My people are motivated by saving the lives of British forces on the battlefield. They are motivated by finding terrorists and serious criminals. If they were asked to snoop, I wouldn't have the workforce, they would leave the building."

6 Why is Britain's legal framework deemed to be so attractive to the US?

Not asked

7 Did GCHQ have legal authority to hack into Google fibre optic cables in the UK?

This was not asked specifically, but Blears put this general question: "Can you give us a guarantee that you do not conduct operations which were outwith the British legal framework."

Lobban replied: "Yes I can give you that guarantee."

8 Did Britain's intelligence agencies receive any transcripts of the mobile phone calls of Angela Merkel and other world leaders?

This was not asked but Tory MP Julian Lewis did question whether Britain's allies were spied on.

Sawers replied: "Everything we do is in response to priorities laid down by government. We have limited resources, of course we don't spy on everyone. There are very few countries where we actively have operations. I'm not going to go into the details."

9 Do Britain's intelligence agencies need warrants for information offered or gifted by another agency such as the NSA?

Not asked

10 Former home secretary David Blunkett said this week the intelligence agencies tended to "get carried away" and their claims needed to be treated with a "breath of scepticism". What do you think he meant? Should Britain's intelligence agencies face stronger oversight?

Rifkind alluded to such concerns by asking: "Very often the agencies themselves seem over-nervous about insisting that something cannot be said in public. Have you sometimes taken that argument too far?"

Parker replied: "The reason why things are secret is not because we are embarrassed about them, it is because we want to keep them from the people that we are investigating."